(a) Field of the Invention
The present invention relates to a display device, and in particular, to a display device that can dissipate heat efficiently from a tape carrier package (TCP) driver integrated circuit (IC) installed on the chassis base that applies an address voltage to a display panel from a driving circuit board.
(b) Description of the Related Art
One example of a commonly used display device is a plasma display device. It is well known that a plasma display device uses plasma generated by gas discharge to display an image on a plasma display panel. Conventionally, in the plasma display device, a flexible printed circuit (FPC) electrically connects electrodes printed on the plasma display panel to a driving circuit. The FPC has an IC that applies an address voltage to form a wall voltage selectively in each pixel in accordance with signals controlled by the driving circuit.
For example, widely used structures using the FPC and the IC to apply the voltage are a chip on board (COB) structure in which the IC is installed on a printed circuit board (PCB), and a chip on film (COF) structure in which the IC is installed on a film composing the FPC. Another structure used recently and more frequently is the TCP, which is small and less expensive.
A COF, COB, or TCP installed on the chassis base produces electromagnetic interference (EMI) as well as a substantial amount of heat. The heat is produced because the gas discharge occurs at least 8 times during 1/60 second (1 TV field), in order to produce more than 256 gradations in the plasma display panel.
Therefore, a reinforcing plate is installed in the COB or COF to reinforce its structure and to fix the COB or COF on the chassis base. The reinforcing plate also plays a role of efficiently dissipating heat generated in the IC to the outside.
With the TCP, by contrast, a heat dissipating plate (or a heat sink) connected to the TCP is installed on the chassis base to dissipate heat from the driver IC to the air.
The heat dissipating plate, installed with the TCP on the chassis base, presses the driver IC to the chassis base, with a stopper consisting of special means placed between the heat dissipating plate and the chassis base to maintain a predetermined space therebetween.
In mass production of the plasma display device, however, the manufacturing tolerance of the chassis base can sometimes cause a non-perfect surface in terms of flatness, where the TCP is attached. In this case, the driver IC may be broken by the heat dissipating plate abnormally pressing the driver IC because the predetermined space is not maintained between the heat dissipating plate and the chassis base.
In addition, the heat dissipating plate in this structure can crush the FPC of the TCP when the heat dissipating plate is fastened with uneven forces of screws. The uneven forces of the screws cause the heat dissipating plate to twist which results in tearing of the FPC.